The third part of a series on alien biology in Doctor Who by James Ashworth, based on his EPQ (extended project qualification) and first published in The Tides of Time number 39, June 2017.

First seen in The Impossible Planet in 2006, the Ood are a race of telepathic beings, who are enslaved across the galaxy. In 2008’s Planet of the Ood, we learned that slave trading firm Ood Operations control them in part by confining the large, separate Ood brain that telepathically links the Ood. Ood Operations ‘process’ the Ood by removing their hind brains, which are responsible for memory and emotion. Are multiple brains possible? In a sense, yes.

It’s a shared mind, connecting all the Ood in song.
– Planet of the Ood

Perhaps the only animal with a comparable attribute is the octopus. In addition to its main brain, it has highly developed neurons in each of its arms, which allow each arm to act independently, acting like smaller brains. In movement, for example, the central brain tells the arms where to point and how far to stretch, but the combination of muscles that are used and how the arm bends is organised by the neurons in the arm itself, in the arrangement of the peripheral neurons and the ganglia in the arms. The arms create their own bends to act as joints by the contraction of muscles. Octopuses have hydrostatic skeletons composed of fluid and muscles. As fluid can’t be compressed, it provides rigidity.

The fact that there are around 320 million neurons in the arms’ nervous system, while the brain contains only 50 million neurons, of around 500 million neurons total in the whole body, shows that the arms must have some degree of intelligence, and can act autonomously. Indeed, the arm suckers secrete chemicals that prevent the arms grasping each other, because they act separately and don’t have a somatotopic area of the central nervous system. This area of the brain informs it where its constituent body parts are, and so without one, its arms may grab each other when instructed to reach for objects. The arms can still move even when amputated, and make complex movements, showing that the arms have a large role in co-ordinating their own movement. However, all these movements exhibited by the octopus’s arm ganglia are equivalent to areas of the main brain, such as the motor cortex, in other organisms such as humans.

There’s a low level telepathic field connecting them. Not that that does them much good.
– The Impossible Planet

Overall, this makes the use of multiple brains in Doctor Who quite realistic, as the main brain of the Ood was where thought occurred, and delegated emotion and memory control to the hindbrain. The principle of a main, central brain being separated into smaller brains, or groups of neurons, with different functions, is perfectly possible and as has been discussed, occurs in the animal kingdom. However, a telepathic, separate brain that is linked to all Ood is so far a fantasy. Unlike the Ponds in Pond Life, we are unlikely to enjoy our own private housekeeping Ood anytime soon. But now this article’s song is ending, and the universe shall sing it to its sleep…